Delaware HVACR Master Mechanic Exam
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Past Papers Questions – Set 100 Most
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Questions And Answers In Details 100%
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Grade A+
1. Which law primarily governs HVACR licensing requirements in Delaware?
A. International Mechanical Code only
B. National Electrical Code only
C. Delaware Board regulations and Delaware Code
D. Federal OSHA regulations only
Answer: C. Delaware Board regulations and Delaware Code
Explanation: The Delaware HVACR Master Mechanic examination is based on
Delaware licensing law, Board regulations, and nationally adopted technical codes.
2. Which refrigerant has zero ozone depletion potential?
A. R-22
B. R-123
C. R-410A
D. R-11
Explanation: R-410A contains no chlorine and therefore has zero ozone depletion
potential.
, 3. Superheat is measured as the difference between:
A. Liquid temperature and condensing temperature
B. Actual suction vapor temperature and saturation temperature
C. Ambient temperature and discharge temperature
D. Condenser temperature and outdoor air temperature
Explanation: Superheat ensures only vapor reaches the compressor.
4. What is the primary purpose of a TXV?
A. Increase condenser pressure
B. Maintain proper evaporator superheat
C. Reduce airflow
D. Increase compressor speed
Explanation: A thermostatic expansion valve controls refrigerant flow to maintain
proper superheat.
5. Which instrument measures airflow?
A. Manometer
B. Clamp meter
C. Anemometer
D. Micron gauge
Explanation: An anemometer measures air velocity.
6. What is the typical target vacuum before charging a refrigeration system?
A. 5000 microns
B. 2500 microns
C. 1000 microns
D. 500 microns or lower
, Explanation: Proper evacuation removes moisture and non-condensables.
7. Excessive subcooling may indicate:
A. Low refrigerant charge
B. Compressor failure
C. Overcharged system or liquid backed up in condenser
D. Dirty evaporator
Explanation: High subcooling often results from excessive refrigerant.
8. A compressor that repeatedly trips on thermal overload most likely
experiences:
A. Low voltage only
B. Overheating or excessive amperage
C. High airflow
D. Low head pressure
Explanation: Thermal overloads protect compressors from overheating.
9. What device prevents reverse refrigerant flow?
A. Solenoid valve
B. Expansion valve
C. Check valve
D. Receiver
Explanation: Check valves allow one-way flow.
10.According to electrical safety practices, equipment should always be:
A. Painted
B. Lubricated
Newest (2025 - 2026 Update) From Real
Past Papers Questions – Set 100 Most
Common Exam Frequently Tested
Questions And Answers In Details 100%
Verified Exam Highly Recommendable For
Grade A+
1. Which law primarily governs HVACR licensing requirements in Delaware?
A. International Mechanical Code only
B. National Electrical Code only
C. Delaware Board regulations and Delaware Code
D. Federal OSHA regulations only
Answer: C. Delaware Board regulations and Delaware Code
Explanation: The Delaware HVACR Master Mechanic examination is based on
Delaware licensing law, Board regulations, and nationally adopted technical codes.
2. Which refrigerant has zero ozone depletion potential?
A. R-22
B. R-123
C. R-410A
D. R-11
Explanation: R-410A contains no chlorine and therefore has zero ozone depletion
potential.
, 3. Superheat is measured as the difference between:
A. Liquid temperature and condensing temperature
B. Actual suction vapor temperature and saturation temperature
C. Ambient temperature and discharge temperature
D. Condenser temperature and outdoor air temperature
Explanation: Superheat ensures only vapor reaches the compressor.
4. What is the primary purpose of a TXV?
A. Increase condenser pressure
B. Maintain proper evaporator superheat
C. Reduce airflow
D. Increase compressor speed
Explanation: A thermostatic expansion valve controls refrigerant flow to maintain
proper superheat.
5. Which instrument measures airflow?
A. Manometer
B. Clamp meter
C. Anemometer
D. Micron gauge
Explanation: An anemometer measures air velocity.
6. What is the typical target vacuum before charging a refrigeration system?
A. 5000 microns
B. 2500 microns
C. 1000 microns
D. 500 microns or lower
, Explanation: Proper evacuation removes moisture and non-condensables.
7. Excessive subcooling may indicate:
A. Low refrigerant charge
B. Compressor failure
C. Overcharged system or liquid backed up in condenser
D. Dirty evaporator
Explanation: High subcooling often results from excessive refrigerant.
8. A compressor that repeatedly trips on thermal overload most likely
experiences:
A. Low voltage only
B. Overheating or excessive amperage
C. High airflow
D. Low head pressure
Explanation: Thermal overloads protect compressors from overheating.
9. What device prevents reverse refrigerant flow?
A. Solenoid valve
B. Expansion valve
C. Check valve
D. Receiver
Explanation: Check valves allow one-way flow.
10.According to electrical safety practices, equipment should always be:
A. Painted
B. Lubricated
